Triumphrat

ANTON58

Hi Guys! Im new to this site but maybe someone can help out?
Did a rebore a few weeks ago on my 1970 bonneville after dropping a valve and ******* the head and cylinder. After the rebuild it lasted 38 miles the motor got realy hot and put a hole in the piston
I put this down to the ignition timing? So another set of pistons went in and a new boyer ignition
Ive just started the bike no big problems but one of the cylinders are getting very hot (making the header glow) Any ideas?
Anybody had this problem?

propforward

Hi Anton,

I'm going to move your post into classics, vintage and veteran section, where there is some great expertise on the older triumphs.

Welcome to the site!

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Snakeoil

If you are sure that the timing is right, sounds like a lean fuel mixture to me. How does the plug in that cylinder look? Maybe crud in the offending carb? Did you rebuild the carbs? Go back and make sure you did everything right if you had the carbs apart.
regards,
Rob

koifarm

Kind of common among the older bikes. My 66 bonnie holed a piston while down in Daytona at bike week back in the 70's. It was a combination of poor valve adjustment and too lean a mixture.
You really have to keep up on tuning the older ones, they require frequent valve checks and plug changes and ignition points .
That's what is soooo nice about the retro's.

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GrandPaulZ

Could be:

Timing too advanced

Carb mix too lean

Piston/cylinder clearance too tight

Any combination of the above.

Welcome to the forum!

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slimmer

If the timing was off wouldn't both cylinders run hot? I would check the valves . Not saying that it is not the timing i am just curious myself because my bike looks hotter on one side then the other by just going with the bluing of the new pipes.

ANTON58

Your right guys!! It looks like an air leak between the carb/manifold I should have seen that one. Ive also done the timing. So its road test time??? I'll get back to ya all with the results.

If it blows up again im goinna kill my wife kids and cat.

If i can sort the picture thing out i'll post some pics of the bikes (Triumphs of corse)
Thanks again.

dledinger

HAHAHAHA!